Wednesday, October 28, 2009

The rains on Oct 26 produced a minor flow event within Onion Creek. About 2-3 inches of rain fell in the Onion Creek watershed (contributing zone) upstream of the Barton Springs segment of the Edwards Aquifer. Flow within the Onion Creek at Driftwood reached a peak discharge of about 514 cfs at 7:30 pm. Peak flow reached the Antioch Cave Recharge facility about 7 hours later (it is about 13 miles downstream).

Antioch Cave is the largest-capacity recharge feature in the District. The District has recently completed a renovation of the recharge facility. The vault that overlies the entrance to Antioch Cave has two valves that can open, allowing recharge to the aquifer. The idea is that the valves are closed during the first part of a flood event, and then will open automatically as the water becomes cleaner. Click here to see the TCEQ's data for the site.

Here's the vault and recharge facility at Antioch Cave on the afternoon of Oct 26.

Here's the same vault a day later! Note the whirlpool above the vault.

Friday, October 23, 2009

The Barton Springs/Edwards Aquifer Conservation District has been in a very restrictive Critical Stage drought for about 10 months. Water use was curtailed by 30%, and outdoor uses such as lawn watering were prohibited. The groundwater users in the District finally received a little bit of good news today when it was announced that the recent rains had increased recharge and sufficiently improved aquifer conditions such that Critical Stage Drought was no longer indicated. At its meeting Thursday night, the Board of Directors changed the declaration to the next less restrictive stage, Alarm Stage drought, to be in effect immediately. Under Alarm Stage drought, users are still mandated to reduce their monthly water use by at least 20% from their authorized amounts, but it does allow some small amount of outdoor water use.

“The local groundwater drought is not over,” noted Kirk Holland, the District’s General Manager, “but we finally received enough rain in the right places to start having some effective replenishment of the aquifer. However, all our groundwater users need to continue to conserve water and use it wisely in order for the higher water levels in the aquifer to be sustained.” Holland expressed some hope that the El Nino climatological conditions would continue to bring the local rains that support creek flows so that in the near future the drought might eventually be completely broken and the restrictions lifted. “We aren’t there yet. But that would be a welcome relief for our groundwater users who have borne the brunt of water use restrictions for two summers and whose demand-reduction efforts have been successful in preserving the water supply for themselves and others,” he said.

The Barton Springs/Edwards Aquifer Conservation District provides scientific, educational, and regulatory programs involved in managing the groundwater resources that serve more than 50,000 people, schools, businesses, industries, and organizations in southern Travis, northern Hays, and western Caldwell and Bastrop Counties.

Last night (10.22.9) the Board of Directors voted to down-grade the drought status from Critical to Alarm Stage based on the status of the District's two drought indicators, Barton Springs and the Lovelady Well.

Barton Springs is averaging near 50 cfs, well above its drought thresholds. In a matter of days the water level in the Lovelady will cross its Alarm Stage threshold of 192.1 ft depth to water. Given the current data and trends, and rather than wait weeks until the next Board Meeting, the Board voted to change the status to Alarm.

However, despite these rains, we are not completely out of the drought--Alarm still requires 20% conservation. A recent article by the Austin American Statesman has a similar conclusion, click here to read more.

Thursday, October 22, 2009

We are on track to leave Critical and enter into Alarm Stage drought at the end of October if the current trend in the Lovelady well continues. The Alarm threshold for the Lovelady well is 192.1 ft depth to water.

However, we are not out of the woods yet, and if we don't get more rain in the upcoming months, we'll be headed back toward Critical Stage. This is evident in the fact that Barton Springs never quite reached average conditions (~60 cfs) despite all the recent rains, and has started to decline slowly.

Thursday, October 15, 2009

The current rain is helping to generate some modest recharge. Barton Springs is currently about 52 cfs and appears to be leveling off.

The Lovelady well has been slowly rising about 0.1 ft/day from late September through October 9. Since October 9 the rate rise has increased to about 0.3 ft/day. At that rate it might be above its Critical threshold (192.1 ft) by Late October--perhaps sooner if we get more rain.

Wednesday, October 7, 2009

The recent rains have put a major dent in the annual deficit. But to date they have not busted the drought. As stated below, we need more rain to get out of our groundwater drought.

Barton Springs has responded very quickly to the rainfall, rising up to nearly 50 cfs. However, the rise is only temporary and has already started to decline. Conversely, the Lovelady Well is slowly rising in response to the modest amount of recharge. Although the behavior of each drought trigger appears to give conflicting information, the response is expected. Barton Springs will respond to minor recharge events, while the Lovelady Well will not. In this case, the Lovelady well is a better representation of the effective recharge to the system. It shows a modest increase in storage, but is not yet above its drought thresholds.

Thursday, October 1, 2009

The Austin American Stateman (by Nathan Adkisson) report that climate specialists indicate that the mild El Nino conditions are expected to ease the drought of Central Texas. However, there is also a word of caution in the article that not all El Nino events generate higher-than-average rainfall. Thus, there are no guarantees that this El Nino will generate more rain. In fact, El Nino events only generate 30% more rainfall on average. That would still not erase the deficit we've accumulated over the past 2 years and the article states that we still may emerge from winter with a deficit of rainfall.

For the (hydrologic) drought to end for the Barton Springs segment of the Edwards Aquifer rainfall has the added requirement of falling (in abundance) in the right location--that is within the contributing watersheds (e.g. Hill Country).

Drought Rules

Either Barton Springs OR the Lovelady Well can trigger a drought declaration by the Board. However, BOTH Barton Springs AND the Lovelady Well must be above their respective drought trigger levels to exit a drought declaration.